| 摘要 |
1,125,576. Screw-and-nut gearing; cams; valves. COMMISSARIAT A L'ENERGIE ATOMIQUE, and P. VULLIEZ. 8 Feb., 1966 [19 Feb., 1965], No. 5500/66. Headings F2K, F2Q and F2V. Valve control means comprise coaxial shafts 1, 2 carrying at their upper ends crank-pins 3, 4 and rollers 5, 6 which engage a cam-groove 7 in a worm-wheel 8, and being splined at their lower ends to screw-threaded bushings 13, 14. Bushing 14 has an extension 18 which contains a piston 10 integral with the gate of the valve and has a screw-threaded connection, of relatively small pitch, with the bushing 13 which has a screw-threaded connection, of relatively coarser pitch, with a valve case 16. During the first half-rotation of wheel 8, shaft 2 remains stationary and bushing 13 rotates to effect rapid downward movement of piston 10 towards the valve closure position. During the second half-rotation of wheel 8, shaft 1 remains stationary and bushing 14 is rotated to complete the downward motion of piston 10 slowly. An assembly of flexible washers 19 holds the gate to its seating in the closed position. |
