| 摘要 |
1,068,221. Converting rotary motion into reciprocating motion; valves; links. COMMISSARIAT A L'ENERGIE ATOMIQUE. Feb. 8, 1966 [Feb. 19, 1965], No. 5501/66. Headings F2K, F2Q and F2V. A mechanism converting rotary motion of a worm-wheel 9, driven by a worm 11, into linear motion of a driven piston (1, Fig. 1, not shown) comprises a disc 2, rotatable in the big end of a connecting-rod 20, the little end of which resiliently engages the piston 1, and also eccentrically rotatable on an eccentric portion 3 of a shaft 4 rotatable about a fixed axis 15, the disc 2 and shaft 4 having crank-pins 6, 7, respectively, which engage in a cam groove 8 in the face of the worm-wheel 9, the cam groove being so shaped that on rotation of the wheel 9, first one eccentric is rotated alone, and then the other is rotated alone. The mechanism provides rapid initial movement and slower final closing of a valve closure member operationally connected to the piston (1). A gudgeon pin member (21) is resiliently urged towards the end of the connecting-rod (20) by Belleville washers (23) to provide a resilient seating load on the valve closure member in the closed position thereof. Starting with the valve fully open, the crank-pins 6, 7 are at positions A 0 , B 0 , respectively (Fig. 3). During a half-revolution of the wheel 9 the pin 7 is engaged in a semi-circular portion 25 of the groove 8, so that the shaft 4 does not rotate, while the pin 6 is moved by a portion 26 of the groove to a position A 2 , the disc 2 being rotated through 180 degrees to displace the piston (1). During a second halfrevolution of the wheel 9, the pin 6 is engaged in the portion 25 so that the disc 2 does not rotate, while the pin 7 is moved by a portion 27 of the groove to a position B 2 , the shaft 4 being rotated through 180 degrees to displace the piston (1) a further, smaller amount to seat the valve closure member. |
