| 摘要 |
1,129,566. Air dashpots. ERICKSON TOOL CO. 12 May, 1966 [14 Feb., 1966], No. 21086/66. Heading F2S. A pneumatic piston and cylinder shockabsorber for cushioning, or decelerating, the indexing movement of an index plate of an index fixture immediately prior to it reaching the final indexed position, comprises a piston 16 which is sealed in a working cylinder and which has a rod 17 which extends through openings 18, 19 respectively in a cylinder head 20 and the housing 2 of the index fixture 3 to be reciprocated by the latter, air ports 21, 26 leading to atmosphere being provided in the heads 20, 25 of the cylinder 15 which is also provided with one or more longitudinally extending-grooves 34. The bore 26 leads to a transverse bore 27 which is controlled by a needle valve 29 and which communicates with central opening 28 connected to the atmosphere through a nozzle 33 and to the interior of the cylinder by means of a one-way flap valve 31. The piston 16 can move relatively freely as the rod 17 is withdrawn from the cylinder 34 air passing out of the cylinder through the point 21, and into it at the opposite end through the opening 28 and the one way valve 31, air also passing from one side of the piston to the other through the grooves 34. Contraction of the shock-absorber is relatively free until the piston 16 passes the corresponding ends of the grooves 34 after which the final movement of the piston 16 is cushioned since air is only able to escape from the cylinder through the port 26, the bores 27, 28 and the nozzle 33, the valve 31 being closed. |
